The aim of the study was to present the frequency of acute drug overdosing by dependent patients in the years 1997, 1998, 1999 and 2000, and to compare the numbers of poisoned addicts suffering withdrawal syndrome and seeking detoxification. The analysis includes data for all drug addicts treated at the Kraków Department of Clinical Toxicology in years 1997, 1998, 1999 and 2000 because of drug overdosing and resultant acute intoxication, because of withdrawal syndrome and also the opiate dependent patients qualified to methadone maintenance programme. The patients dependent on ethanol were excluded. A progressive increase in number of poisonings with psychoactive substances was noted in analysed years, respectively 231, 298, 331 and 442 patients. Drugs of abuse, were the most frequent cause of admission. Also incidence rate of poisoning expressed per 10,000 of Kraków inhabitants was highest for the cases admitted because of overdosing or craving for narcotics. Opiate derivatives produced at home from poppy straw or from juice of poppy head (so called "kompot" or "Polish heroin") were the most common cause of admission in all the analysed years: increase in number of acutely poisoned, and also increase in number of opiate dependent patients who suffered withdrawal syndrome and sought detoxification was noted in 2000 as compared to years 1998 and 1999. Opiate derivatives followed by amphetamine, as the single toxic agent or in mixed combinations, were still the most common drugs of abuse detected in body fluids. The men were dominant in all the analysed years, but the increase in number of depended women was observed through the years under analysis.